Z_INDEX_BASE

Properties

events

Register a listener for a particular event with the following syntax

Listeners will be called with a reference to an event object. The properties of this event depends on exactly what happened.

All event objects have at least the following properties

object

{Object} A reference to map.events.object.

element

{DOMElement} A reference to map.events.element.

Browser events have the following additional properties

xy

{OpenLayers.Pixel} The pixel location of the event (relative to the the map viewport).

Supported map event types

preaddlayer

triggered before a layer has been added. The event object will include a layer property that references the layer to be added. When a listener returns “false” the adding will be aborted.

addlayer

triggered after a layer has been added. The event object will include a layer property that references the added layer.

preremovelayer

triggered before a layer has been removed. The event object will include a layer property that references the layer to be removed. When a listener returns “false” the removal will be aborted.

removelayer

triggered after a layer has been removed. The event object will include a layer property that references the removed layer.

changelayer

triggered after a layer name change, order change, opacity change, params change, visibility change (actual visibility, not the layer’s visibility property) or attribution change (due to extent change). Listeners will receive an event object with layer and property properties. The layer property will be a reference to the changed layer. The property property will be a key to the changed property (name, order, opacity, params, visibility or attribution).

movestart

triggered after the start of a drag, pan, or zoom. The event object may include a zoomChanged property that tells whether the zoom has changed.

move

triggered after each drag, pan, or zoom

moveend

triggered after a drag, pan, or zoom completes

zoomstart

triggered when a zoom starts. Listeners receive an object with center and zoom properties, for the target center and zoom level.

id

fractionalZoom

{Boolean} For a base layer that supports it, allow the map resolution to be set to a value between one of the values in the resolutions array. Default is false.

When fractionalZoom is set to true, it is possible to zoom to an arbitrary extent. This requires a base layer from a source that supports requests for arbitrary extents (i.e. not cached tiles on a regular lattice). This means that fractionalZoom will not work with commercial layers (Google, Yahoo, VE), layers using TileCache, or any other pre-cached data sources.

If you are using fractionalZoom, then you should also use getResolutionForZoom instead of layer.resolutions[zoom] as the former works for non-integer zoom levels.

events

allOverlays

{Boolean} Allow the map to function with “overlays” only. Defaults to false. If true, the lowest layer in the draw order will act as the base layer. In addition, if set to true, all layers will have isBaseLayer set to false when they are added to the map.

Note

If you set map.allOverlays to true, then you cannot use map.setBaseLayer or layer.setIsBaseLayer. With allOverlays true, the lowest layer in the draw layer is the base layer. So, to change the base layer, use setLayerIndex or raiseLayer to set the layer index to 0.

div

{DOMElement|String} The element that contains the map (or an id for that element). If the OpenLayers.Map constructor is called with two arguments, this should be provided as the first argument. Alternatively, the map constructor can be called with the options object as the only argument. In this case (one argument), a div property may or may not be provided. If the div property is not provided, the map can be rendered to a container later using the render method.

Note

If you are calling render after map construction, do not use maxResolution auto. Instead, divide your maxExtent by your maximum expected dimension.

center

resolution

zoom

panRatio

{Float} The ratio of the current extent within which panning will tween.

options

{Object} The options object passed to the class constructor. Read-only.

tileSize

{OpenLayers.Size} Set in the map options to override the default tile size for this map.

projection

{String} Set in the map options to specify the default projection for layers added to this map. When using a projection other than EPSG:4326 (CRS:84, Geographic) or EPSG:3857 (EPSG:900913, Web Mercator), also set maxExtent, maxResolution or resolutions. Default is “EPSG:4326”. Note that the projection of the map is usually determined by that of the current baseLayer (see baseLayer and getProjectionObject).

units

{String} The map units. Possible values are ‘degrees’ (or ‘dd’), ‘m’, ‘ft’, ‘km’, ‘mi’, ‘inches’. Normally taken from the projection. Only required if both map and layers do not define a projection, or if they define a projection which does not define units

resolutions

{Array(Float)} A list of map resolutions (map units per pixel) in descending order. If this is not set in the layer constructor, it will be set based on other resolution related properties (maxExtent, maxResolution, maxScale, etc.).

maxResolution

{Float} Required if you are not displaying the whole world on a tile with the size specified in tileSize.

minResolution

{Float}

maxScale

{Float}

minScale

{Float}

maxExtent

{<OpenLayers.Bounds>|Array} If provided as an array, the array should consist of four values (left, bottom, right, top). The maximum extent for the map. Default depends on projection; if this is one of those defined in OpenLayers.Projection.defaults (EPSG:4326 or web mercator), maxExtent will be set to the value defined there; else, defaults to null. To restrict user panning and zooming of the map, use restrictedExtent instead. The value for maxExtent will change calculations for tile URLs.

minExtent

{<OpenLayers.Bounds>|Array} If provided as an array, the array should consist of four values (left, bottom, right, top). The minimum extent for the map. Defaults to null.

restrictedExtent

{<OpenLayers.Bounds>|Array} If provided as an array, the array should consist of four values (left, bottom, right, top). Limit map navigation to this extent where possible. If a non-null restrictedExtent is set, panning will be restricted to the given bounds. In addition, zooming to a resolution that displays more than the restricted extent will center the map on the restricted extent. If you wish to limit the zoom level or resolution, use maxResolution.

numZoomLevels

{Integer} Number of zoom levels for the map. Defaults to 16. Set a different value in the map options if needed.

theme

{String} Relative path to a CSS file from which to load theme styles. Specify null in the map options (e.g. {theme: null}) if you want to get cascading style declarations - by putting links to stylesheets or style declarations directly in your page.

displayProjection

{OpenLayers.Projection} Requires proj4js support for projections other than EPSG:4326 or EPSG:900913/EPSG:3857. Projection used by several controls to display data to user. If this property is set, it will be set on any control which has a null displayProjection property at the time the control is added to the map.

tileManager

{<OpenLayers.TileManager>|Object} By default, and if the build contains TileManager.js, the map will use the TileManager to queue image requests and to cache tile image elements. To create a map without a TileManager configure the map with tileManager: null. To create a TileManager with non-default options, supply the options instead or alternatively supply an instance of {OpenLayers.TileManager}.

fallThrough

{Boolean} Should OpenLayers allow events on the map to fall through to other elements on the page, or should it swallow them? (#457) Default is to swallow.

autoUpdateSize

{Boolean} Should OpenLayers automatically update the size of the map when the resize event is fired. Default is true.

eventListeners

{Object} If set as an option at construction, the eventListeners object will be registered with OpenLayers.Events.on. Object structure must be a listeners object as shown in the example for the events.on method.

layerContainerOriginPx

minPx

{Object} An object with a ‘x’ and ‘y’ values that is the lower left of maxExtent in viewport pixel space. Used to verify in moveByPx that the new location we’re moving to is valid. It is also used in the getLonLatFromViewPortPx function of Layer.

maxPx

{Object} An object with a ‘x’ and ‘y’ values that is the top right of maxExtent in viewport pixel space. Used to verify in moveByPx that the new location we’re moving to is valid.

Constructor

OpenLayers.Map

Constructor for a new OpenLayers.Map instance. There are two possible ways to call the map constructor. See the examples below.

Parameters

div

{DOMElement|String} The element or id of an element in your page that will contain the map. May be omitted if the div option is provided or if you intend to call the render method later.

options

{Object} Optional object with properties to tag onto the map.

Valid options (in addition to the listed API properties)

center

{<OpenLayers.LonLat>|Array} The default initial center of the map. If provided as array, the first value is the x coordinate, and the 2nd value is the y coordinate. Only specify if layers is provided. Note that if an ArgParser/Permalink control is present, and the querystring contains coordinates, center will be set by that, and this option will be ignored.

zoom

{Number} The initial zoom level for the map. Only specify if layers is provided. Note that if an ArgParser/Permalink control is present, and the querystring contains a zoom level, zoom will be set by that, and this option will be ignored.

Functions

getViewport

Returns

render

Parameters

{String|DOMElement} The container that the map should be rendered to. If different than the current container, the map viewport will be moved from the current to the new container.

unloadDestroy

Function that is called to destroy the map on page unload. stored here so that if map is manually destroyed, we can unregister this.

updateSizeDestroy

When the map is destroyed, we need to stop listening to updateSize events: this method stores the function we need to unregister in non-IE browsers.

destroy

destroy:function()

Destroy this map. Note that if you are using an application which removes a container of the map from the DOM, you need to ensure that you destroy the map before this happens; otherwise, the page unload handler will fail because the DOM elements that map.destroy() wants to clean up will be gone.

getTileSize

Returns

getBy

Parameters

array

{String} A property on the map whose value is an array.

property

{String} A property on each item of the given array.

match

{String | Object} A string to match. Can also be a regular expression literal or object. In addition, it can be any object with a method named test. For reqular expressions or other, if match.test(map[array][i][property]) evaluates to true, the item will be included in the array returned. If no items are found, an empty array is returned.

Returns

{Array} An array of items where the given property matches the given criteria.

getLayersBy

getLayersBy: function(

property,

match

)

Get a list of layers with properties matching the given criteria.

Parameters

property

{String} A layer property to be matched.

match

{String | Object} A string to match. Can also be a regular expression literal or object. In addition, it can be any object with a method named test. For reqular expressions or other, if match.test(layer[property]) evaluates to true, the layer will be included in the array returned. If no layers are found, an empty array is returned.

Returns

{Array(OpenLayers.Layer)} A list of layers matching the given criteria. An empty array is returned if no matches are found.

getLayersByName

getLayersByName: function(

match

)

Get a list of layers with names matching the given name.

Parameters

match

{String | Object} A layer name. The name can also be a regular expression literal or object. In addition, it can be any object with a method named test. For reqular expressions or other, if name.test(layer.name) evaluates to true, the layer will be included in the list of layers returned. If no layers are found, an empty array is returned.

Returns

{Array(OpenLayers.Layer)} A list of layers matching the given name. An empty array is returned if no matches are found.

getLayersByClass

getLayersByClass: function(

match

)

Get a list of layers of a given class (CLASS_NAME).

Parameters

match

{String | Object} A layer class name. The match can also be a regular expression literal or object. In addition, it can be any object with a method named test. For reqular expressions or other, if type.test(layer.CLASS_NAME) evaluates to true, the layer will be included in the list of layers returned. If no layers are found, an empty array is returned.

Returns

{Array(OpenLayers.Layer)} A list of layers matching the given class. An empty array is returned if no matches are found.

getControlsBy

getControlsBy: function(

property,

match

)

Get a list of controls with properties matching the given criteria.

Parameters

property

{String} A control property to be matched.

match

{String | Object} A string to match. Can also be a regular expression literal or object. In addition, it can be any object with a method named test. For reqular expressions or other, if match.test(layer[property]) evaluates to true, the layer will be included in the array returned. If no layers are found, an empty array is returned.

Returns

{Array(OpenLayers.Control)} A list of controls matching the given criteria. An empty array is returned if no matches are found.

getControlsByClass

getControlsByClass: function(

match

)

Get a list of controls of a given class (CLASS_NAME).

Parameters

match

{String | Object} A control class name. The match can also be a regular expression literal or object. In addition, it can be any object with a method named test. For reqular expressions or other, if type.test(control.CLASS_NAME) evaluates to true, the control will be included in the list of controls returned. If no controls are found, an empty array is returned.

Returns

{Array(OpenLayers.Control)} A list of controls matching the given class. An empty array is returned if no matches are found.

getLayer

getLayer: function(

id

)

Get a layer based on its id

Parameters

id

{String} A layer id

Returns

{OpenLayers.Layer} The Layer with the corresponding id from the map’s layer collection, or null if not found.

Returns

addLayers

Parameters

removeLayer

Removes a layer from the map by removing its visual element (the layer.div property), then removing it from the map’s internal list of layers, setting the layer’s map property to null.

a “removelayer” event is triggered.

very worthy of mention is that simply removing a layer from a map will not cause the removal of any popups which may have been created by the layer. this is due to the fact that it was decided at some point that popups would not belong to layers. thus there is no way for us to know here to which layer the popup belongs.

A simple solution to this is simply to call destroy() on the layer. the default OpenLayers.Layer class’s destroy() function automatically takes care to remove itself from whatever map it has been attached to.

The correct solution is for the layer itself to register an event-handler on “removelayer” and when it is called, if it recognizes itself as the layer being removed, then it cycles through its own personal list of popups, removing them from the map.

getNumLayers

Returns

getLayerIndex

Parameters

Returns

{Integer} The current (zero-based) index of the given layer in the map’s layer stack. Returns -1 if the layer isn’t on the map.

setLayerIndex

setLayerIndex: function (

layer,

idx

)

Move the given layer to the specified (zero-based) index in the layer list, changing its z-index in the map display. Use map.getLayerIndex() to find out the current index of a layer. Note that this cannot (or at least should not) be effectively used to raise base layers above overlays.

Parameters

raiseLayer

raiseLayer: function (

layer,

delta

)

Change the index of the given layer by delta. If delta is positive, the layer is moved up the map’s layer stack; if delta is negative, the layer is moved down. Again, note that this cannot (or at least should not) be effectively used to raise base layers above overlays.

addControl

Parameters

addControls

addControls: function (

controls,

pixels

)

Add all of the passed over controls to the map. You can pass over an optional second array with pixel-objects to position the controls. The indices of the two arrays should match and you can add null as pixel for those controls you want to be autopositioned.

addPopup

Parameters

removePopup

Parameters

getSize

getSize: function ()

Returns

{OpenLayers.Size} An OpenLayers.Size object that represents the size, in pixels, of the div into which OpenLayers has been loaded. Note - A clone() of this locally cached variable is returned, so as not to allow users to modify it.

updateSize

updateSize: function()

This function should be called by any external code which dynamically changes the size of the map div (because mozilla wont let us catch the “onresize” for an element)

moveByPx

Parameters

adjustZoom

adjustZoom: function(

zoom

)

Parameters

zoom

{Number} The zoom level to adjust

Returns

{Integer} Adjusted zoom level that shows a map not wider than its baseLayer’s maxExtent.

getMinZoom

getMinZoom: function()

Returns the minimum zoom level for the current map view. If the base layer is configured with <wrapDateLine> set to true, this will be the first zoom level that shows no more than one world width in the current map viewport. Components that rely on this value (e.g. zoom sliders) should also listen to the map’s “updatesize” event and call this method in the “updatesize” listener.

Returns

{Number} Minimum zoom level that shows a map not wider than its baseLayer’s maxExtent. This is an Integer value, unless the map is configured with fractionalZoom set to true.

Returns

isValidLonLat

Parameters

Returns

{Boolean} Whether or not the lonlat passed in is non-null and within the maxExtent bounds

getProjection

getProjection: function()

This method returns a string representing the projection. In the case of projection support, this will be the srsCode which is loaded -- otherwise it will simply be the string value that was passed to the projection at startup.

FIXME: In 3.0, we will remove getProjectionObject, and instead return a Projection object from this function.

Returns

getZoomForExtent

Parameters

{Boolean} Find the zoom level that most closely fits the specified bounds. Note that this may result in a zoom that does not exactly contain the entire extent. Default is false.

Returns

{Integer} A suitable zoom level for the specified bounds. If no baselayer is set, returns null.

getResolutionForZoom

getResolutionForZoom: function(

zoom

)

Parameters

zoom

{Float}

Returns

{Float} A suitable resolution for the specified zoom. If no baselayer is set, returns null.

getZoomForResolution

getZoomForResolution: function(

resolution,

closest

)

Parameters

resolution

{Float}

closest

{Boolean} Find the zoom level that corresponds to the absolute closest resolution, which may result in a zoom whose corresponding resolution is actually smaller than we would have desired (if this is being called from a getZoomForExtent() call, then this means that the returned zoom index might not actually contain the entire extent specified... but it’ll be close). Default is false.

Returns

{Integer} A suitable zoom level for the specified resolution. If no baselayer is set, returns null.

zoomTo

zoomTo: function(

zoom,

xy

)

Zoom to a specific zoom level. Zooming will be animated unless the map is configured with {zoomMethod: null}. To zoom without animation, use setCenter without a lonlat argument.

Parameters

zoom

{Integer}

zoomIn

zoomIn: function()

zoomOut

zoomOut: function()

zoomToExtent

zoomToExtent: function(

bounds,

closest

)

Zoom to the passed in bounds, recenter

Parameters

bounds

{<OpenLayers.Bounds>|Array} If provided as an array, the array should consist of four values (left, bottom, right, top).

closest

{Boolean} Find the zoom level that most closely fits the specified bounds. Note that this may result in a zoom that does not exactly contain the entire extent. Default is false.

zoomToMaxExtent

zoomToMaxExtent: function(

options

)

Zoom to the full extent and recenter.

Parameters

options

{Object}

Allowed Options

restricted

{Boolean} True to zoom to restricted extent if it is set. Defaults to true.

zoomToScale

zoomToScale: function(

scale,

closest

)

Zoom to a specified scale

Parameters

scale

{float}

closest

{Boolean} Find the zoom level that most closely fits the specified scale. Note that this may result in a zoom that does not exactly contain the entire extent. Default is false.

getLonLatFromViewPortPx

getLonLatFromViewPortPx: function (

viewPortPx

)

Parameters

viewPortPx

{<OpenLayers.Pixel>|Object} An OpenLayers.Pixel or an object with a ‘x’ and ‘y’ properties.

Parameters

Returns

applyTransform

applyTransform: function(

x,

y,

scale

)

Applies the given transform to the layerContainerDiv. This method has a 2-stage fallback from translate3d/scale3d via translate/scale to plain style.left/style.top, in which case no scaling is supported.